CVE-2024-40643 — Joplin is a free, open source note taking and to-do application

Joplin is a free, open source note taking and to-do application. Joplin fails to take into account that "<" followed by a non letter character will not be considered html. As such it is possible to do an XSS by putting an "illegal" tag within a tag.

01What is this vulnerability?

Joplin is a free, open source note taking and to-do application. Joplin fails to take into account that "<" followed by a non letter character will not be considered html. As such it is possible to do an XSS by putting an "illegal" tag within a tag.

02Affected products

Vendor	Product	Versions
laurent22	joplin	< 3.0.15

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

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07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2024-09-09T14:28:20.920Z
• Last modified: 2024-09-09T14:52:47.111Z

09References

• github.com — https://github.com/laurent22/joplin/security/advisories/GHSA-g796-3g6g-jmmc
• github.com — https://github.com/laurent22/joplin/commit/b220413a9b5ed55fb1f565ac786a5c231da8b…